Development of photo-crosslinked elastomeric materials

P. GUARAS; J.P. TOMBA; C. J. PÉREZ

Mar del Plata

Simposio; XVI Simposio Latinoamericano de Polimeros; 2018

Division Polimeros-INTEMA

Semicrystalline thermoplastic elastomers (SCTPE) comprise an important family of products in elastomer industry. SCTPE are designed to have thermoplastic-like processability and elastomeric behaviour. However, they cannot achieve the same level of mechanical performance than a traditional chemically crosslinked rubber. For instance, SCTPE show undesirably higher creep and compression set values than the vulcanized counterparts, which limit their application in more demanding situations.One way of improving SCTPE properties is via chemical modification. For example, crosslinking is among the most broadly post-reactor modification procedures applied to polyolefins. There are various alternative methods for introducing crosslinks between the polyolefins chains, but ionizing radiation and organic peroxide crosslinking are the most used in the industry.Crosslinking of SCTPE can be achieved within seconds upon UV exposure, when a polymer is blended with a photo-initiator and a crosslinking agent. UV-curing creates covalent bonds between chains, thus reinforcing the already existing physical network. It is also a process that occurs in a single stage, with simple and cheap equipment, as the material can be treated with radiation after extruding/injecting the piece by traditional methods.In this work, a SCTPE based on random and a block ethylene-octene copolymer have been used to produce photocrosslinking with improved mechanical properties. It is carried out by incorporating a photoiniciator and a crosslinking agent to the original SCTPE formulation, in the melt state. Variables such as exposition time and additives content are examined. The occurrence of crosslinking reaction is monitored by rotational rheology. To evaluate the effectiveness of the chemical modification compression set of samples are measured.